One method of manufacturing products is what is termed a line production method, which uses a conveyor belt. In this line production method, a plurality of stations is provided along a conveyor line, and at each station, there is an operator positioned with manufacturing equipment, tools, parts, materials and the like. In addition, workpieces are conveyed in sequence by a conveyor belt, prescribed operating steps are carried out at the respective stations, and the product is thereby manufactured. While this line production method is suitable for mass production, a large capital expenditure is necessary, and when the product specifications are changed, this method cannot readily and flexibly respond.
In recent years, in order to respond to the diversification of consumer needs and the like in the field of automobile production and electrical equipment production, the need to manufacture many models in small lots has been increasing. In place of the line production method, a cell manufacturing method, in which one operator carries out a plurality of operation steps, is gradually coming into use as a production method that is suitable for this small-scale production of many models. In the cell manufacturing method, there are the advantages that the response to product specification changes is facilitated and capital expenditures can be reduced. In addition, from the point of view of the operator, the method will be embraced willingly because there is an awareness that the product has been completed by himself.
Japanese Patent Application Publication No. JP-A-2003-251575, for example, discloses an example of a cell manufacturing method in which a workpiece is mounted on a hand-pushed operating car, and operations are carried out while the car transits the plurality of stations. In addition, a means to raise and lower the workpiece is provided, and improvements in productivity and a reduction in the operator fatigue can be realized.
However, in the cell manufacturing method of Patent Document 1, while the operating car is in motion, the operation steps do not proceed, and it cannot be said that the productivity is sufficient. Thus, a significant increase in efficiency and a reduction in production lead time can be expected. Furthermore, there are cases in which parts that are pre-assembled by combining component parts are necessary, and the problems of eliminating storage space and the labor for managing these parts remain. In addition, when one operator carries out all operation steps, including the operations for the sub-assembly, the number of stations becomes too large, the movement distance is drastically increased, and the content of the operation is complex. Thus, there are cases in which this cannot be adopted as a suitable production method.
In consideration of these circumstances, aspects of the present invention provide a cell manufacturing method and a cell manufacturing facility that significantly increases the productivity beyond that of the related art, can reduce production lead time, minimizes the amount of parts requiring storage, and distributes the operation steps among a plurality of operators.